The present invention relates generally to plasma cutting/welding-type systems and, more particularly, to a method and apparatus for providing a high power density plasma cutting/welding-type system.
Plasma cutting is a process in which an electric arc and plasma gas are used to cut or gouge a workpiece. Plasma cutters typically include a power source, a gas supply, such as compressed air, and a torch. The torch is constructed to create and maintain the plasma arc. To generate the plasma cutting power, a power source receives an input voltage from a transmission power receptacle or generator and provides output power to a pair of output terminals. One of the output terminals is connected to an electrode and the other is connected to the workpiece. An air supply is used with most plasma cutters to carry and propel the arc to the workpiece and assist in cooling the torch.
The need and desire for plasma cutting systems to become portable has increased over the years. To achieve this portability, plasma cutting systems have been designed to have lighter unit weights and improved electrical components. One advancement in the area of electrical components has been the incorporation of inverter-type power sources. The application of an inverter power source has reduced the size and weight of plasma cutters and created usable space within the confines of the housing, while maintaining the ability to generate the outputs required for plasma cutting.
In existing plasma cutting systems, however, there have been limits to the reductions in size that are achievable. Existing plasma cutting systems typically include a gas supply system including a pressure regulator; a downstream pressure gauge; a downstream, solenoid operated gas valve; and a downstream pressure limit switch, so as to provide the plasma torch with a consistent, and preferably controllable, air flow. Using such a configuration, the operator is able to start and stop the gas flow as necessary, as well as access and adjust gas pressure settings to configure the plasma cutting system for a different cutting operation. However, while control of air pressure settings in this manner provides an operator with a great deal of control, such a construction also occupies a great deal of space within the plasma cutter and necessarily increases the overall size and weight of the plasma cutter.
It would, therefore, be desirable to design a plasma cutting system having a reduced size and weight that still provides for a precise and dynamic gas pressure regulation. It would further be desirable for such a reduced size/weight system to have the ability to produce a high power density, so as to generate the outputs required for plasma cutting.